diff --git a/pkg/normalize/validate.go b/pkg/normalize/validate.go
index b47e1f49e..1d82da5c3 100644
--- a/pkg/normalize/validate.go
+++ b/pkg/normalize/validate.go
@@ -90,6 +90,7 @@ var labelUnderscores = []string{
 	"_acme-challenge",
 	"_amazonses",
 	"_dmarc",
+	"_domainconnect",
 	"_domainkey",
 	"_jabber",
 	"_mta-sts",